Generally speaking, a scroll apparatus used for a refrigeration apparatus comprises two spiral scroll wraps mounted on a separate end plate to define a scroll member. The two scroll wraps the above are intermitted together with one of them being rotationally displaced 180 degrees from the other.
FIG. 1 of the attached drawing figures is a vertical sectional view of the conventional scroll-type compressor, which comprises stator 1 and rotor 2 to generate rotation power, crankshaft 3 heat thrust into the above rotor 2, rotation pin 4 with the center eccentric from that of the above crankshaft 3, rotation bush 5 surrounding the outer circumference of the above rotation pin 4, orbiting scroll 7 installed on the outer circumferential surface of the above rotation bush 5 and compressing the refrigerant inhaled simultaneously at two parts of the scroll circumference through inhalation duct 6 by way of the orbital motion in accordance with the rotation of the above crankshaft 3, fixed scroll or non-orbiting scroll 8 fixed at main frame 17 in opposition to the top plate of the above orbiting scroll 17, compression chamber 9 to compress the refrigerant gas inside the above fixed scroll 8, exhalation outlet 10 exhaling the refrigerant of high pressure coming out of the above compression chamber 9, exhalation chamber 11 storing the above exhaled refrigerant temporarily, and circular cylindrical steel shell 12 containing all of the above mention components inside.
And between the above fixed scroll 8 and top diaphragm 18, pressure distribution chamber 14 is located, which pushes fixed scroll 8 toward orbiting scroll 7 by distributing the pressure of refrigerant gas drawn in from compression chamber through pressure distribution bore 13.
The indescribed code 15 of the above drawing figure is a leaf spring to fix the above fixed scroll 8 at main frame 17 by connecting with bolt 18.
The description of the movements of a scroll-type compressor with the above configuration and the problems thereof is as follows:
The refrigerant gas inhaled through inhalation duct 6 is inhaled simultaneously at two parts of the scroll circumference in accordance with the orbital motion of orbiting scroll 7.
The two symmetrical crescent-shaped pockets of fluid formed in accordance with inhaling actions of refrigerant by the above orbiting scroll 7 are compressed and move toward the center with the reduction of volume.
And the pocket figures compressed in the center are intermixed and exhaled through exhalation outlet 10.
The process from inhalation to exhalation is usually completed if crankshaft 3 rotates around 2-3 times.
However, at the time of inhalation during the above process, the refrigerant gas is leaked from a pocket of high pressure to a pocket of low pressure through two kinds of course. One is leakage caused by the gap between tip members 19 and 20 of fixed scroll and orbiting scroll wraps and an end plate of the other scroll, which is referred to as axial leakage, and the other is leakage caused by the gap between wraps of both scrolls 7 and 8, which is referred to as radial direction leakage.
In consideration of the quantity of entire leakage, the axial leakage is much greater than the radial direction leakage and its disposal is necessarily required.
The conventional technique to prevent the axial leakage of a scroll compressor like this is illustrated in FIG. 22. As shown in the drawing figure, it is configured that fixed scroll 8 and main frame 17 are assembled by connecting with bolt 16 through leaf spring 15 and pressure distribution chamber 14 with a regular cross-sectional area is located at the rear plate of the above fixed scroll 8.
While the compression process proceeds in the above configuration, the compressed gas with pressure of F1 is sent to pressure distribution chamber 14 through pressure distribution bore 13. The compressed gas distributed with the regular pressure in pressure distribution chamber 14 puts pressure of F2 on fixed scroll 8.
As fixed scroll 8 moves downward by distributed pressure F2 put on the above fixed scroll 8, this minimizes the gap between tip members 19 and 20 of the scroll wrap and an end plate of the other scroll, which minimizes the axial leakage caused in this gap.
A scroll-type compressor to prevent the axial leakage like this is mentioned in the precedent technology such as U.S. Pat. Nos. 3,874,827 and 4,877,382.
But the architecture to prevent the axial leakage by using the pressure of pressure distribution chamber 14 in this manner has a problem that the power loss is caused, because it is designed to extract and use a part of the compressed gas. This fact can be found from volume versus pressure change graph of FIG. 3. That is, as illustrated in the graph, it shows that the power loss has been caused as much as the part obliquely lined due to the linkage of compression chamber 9 and pressure distribution bore 13 in a section (S) marked on a horizontal axis, in the process that the volume is expanded and compressed.